Hoang Dinh Nam | AFP | Getty Images
Villagers walk past the native home of Doan Thi Huong, a suspect involved in the assassination of Kim Jong-Un's half-brother, in Nghia Hung district, northern province of Nam Dinh on February 22, 2017.
A member of the Vietnam Idol casting team declined to comment on the appearance and its spokeswoman did not immediately return a request for comment.
"Can I sing you a song tonight?" she wrote in a Facebook post on March 24 last year. "Reply the fastest and put your phone number in the comment. I will call and sing for you."
Family members mostly work the rice paddies around their home in Nam Dinh, in the Red River Delta southeast of Hanoi.
Huong only visited occasionally, they said, and she was vague about where she had been. She is now 28.
Her father, who fought for the North in the Vietnam War, lost part of his leg in the fighting. Vietnamese authorities had been in touch since the arrest, he said.
"They only say they will support Huong as she is Vietnamese, but did not tell me if she is really a suspect," he told Reuters.
"Even though I am her father I cannot control things that happened when she is out there. I cannot know," said Doan Van Thanh, 63, who works as a security guard in the local market.
Family members said they only found out she was abroad from the media. They had thought she was working in Hanoi.
So far, Vietnamese officials have only confirmed to media that investigations continue and they are in touch with Malaysia.